I'm trying to perform a track conversion and I have made many progress, but there is something very strange that happens with the shadows. I have tried different cars, but same result. P.S. This happens to all track's shadows Here is the video dimonstration: https://gfycat.com/GrippingAcidicAmericanshorthair
If nobody have ever had such a problem, it's hard to help. In such cases, i always would suggest to upload your mod and offer a link, that we can try to reproduce it and try to find the reason for the problem.
Problem solved, a moveable object in the sky (helicopter) was a shadow caster, shadow instance removed and now work perfectly fine